OBJECTIVE To explore the mechanism of gallic acid targeting β-arrestin2 to inhibit astrocyte inflammation.METHODS Potential targets of gallic acid were found by PharmMapper and verified by thermal shift and molecular docking experi-ments.Western blot was used to detect the expression of β-arrestin2,NF-κB signaling pathway and NLRP3 inflammasome-related proteins;qPCR was used to detect the mRNA levels of proinflammatory cytokines such as IL-1β,IL-6 and TNF-α.A subacute PD mouse model induced by MPTP was established,and the behavioral ability of mice was evaluated by open field test,rotating rod test and climbing pole test;the number of TH+and GFAP+cells in the SNc area of mice was detected by immunohistochemistry;Western blot was used to detect the expression of NF-κB signaling pathway and NLRP3 inflammasome-related proteins in the homogenate pro-tein of mouse midbrain tissue.RESULTS Molecular docking experiments and thermal shift experiments showed that gallic acid could directly bind to β-arrestin2.Gallic acid could reduce the expression of p-IKK and p-P65 proteins in astrocytes(P<0.001,P<0.000 1),reduce the mRNA levels of IL-1β,IL-6 and TNF-α(P<0.05,P<0.01),and reduce the expression of caspase-1 and IL-1β proteins(P<0.000 1),but had no effect on the expression of β-arrestin2 protein(P>0.05).Gallic acid could improve the be-havioral ability of PD model mice,increase the number of TH+neurons and GFAP+cells in PD model mice(P<0.05,P<0.001),and reduce the expression of caspase-1,IL-1β,NLRP3 and p-IKK proteins in the brain of PD model mice(P<0.05).CONCLU-SION Gallic acid inhibits the activation of NF-κB signaling pathway and NLRP3 inflammasome by binding to β-arrestin2 to reduce astrocyte inflammation,and has a neuroprotective effect on MPTP-induced PD model mice.

Extensive evidence has demonstrated that glucagon-like peptide-1 receptor agonists (GLP-1RAs) can ameliorate obesity. Our previous studies revealed that (Ex-4)₂-Fc, a long-acting GLP-1RA we developed, depends on the leptin pathway to treat obesity. However, the mechanisms linking (Ex-4)₂-Fc and leptin resistance remain largely unclear. To address this question, we explored the mechanism of GLP-1RAs from the perspective of the gut microbiota, as increasing evidence indicates an important link between the gut microbiota and obesity. This study aimed to explore the potential role of the gut microbiota in the treatment of GLP-1RAs. We found that (Ex-4)₂-Fc treatment reshaped obesity-induced gut microbiota disturbances and substantially increased the abundance of Akkermansia muciniphila (Am). In addition, (Ex-4)₂-Fc did not respond well in antibiotic-treated (ATB) Obese mice. Subsequent studies have shown that this defect can be overcome by gavage with Am. In addition, we found that Am enhanced (Ex-4)₂-Fc therapy by producing the metabolite inosine. Inosine regulates the macrophage adenosine A2A receptor (A2A) pathway to indirectly reduce leptin levels in adipocytes Thus, elucidating the role of metabolites in regulating the leptin pathway will provide new insights into GLP-1RAs therapy and may lead to more effective strategies for guiding the clinical use of antidiabetic agents.

OBJECTIVE To explore the mechanism of gallic acid targeting β-arrestin2 to inhibit astrocyte inflammation.METHODS Potential targets of gallic acid were found by PharmMapper and verified by thermal shift and molecular docking experi-ments.Western blot was used to detect the expression of β-arrestin2,NF-κB signaling pathway and NLRP3 inflammasome-related proteins;qPCR was used to detect the mRNA levels of proinflammatory cytokines such as IL-1β,IL-6 and TNF-α.A subacute PD mouse model induced by MPTP was established,and the behavioral ability of mice was evaluated by open field test,rotating rod test and climbing pole test;the number of TH+and GFAP+cells in the SNc area of mice was detected by immunohistochemistry;Western blot was used to detect the expression of NF-κB signaling pathway and NLRP3 inflammasome-related proteins in the homogenate pro-tein of mouse midbrain tissue.RESULTS Molecular docking experiments and thermal shift experiments showed that gallic acid could directly bind to β-arrestin2.Gallic acid could reduce the expression of p-IKK and p-P65 proteins in astrocytes(P<0.001,P<0.000 1),reduce the mRNA levels of IL-1β,IL-6 and TNF-α(P<0.05,P<0.01),and reduce the expression of caspase-1 and IL-1β proteins(P<0.000 1),but had no effect on the expression of β-arrestin2 protein(P>0.05).Gallic acid could improve the be-havioral ability of PD model mice,increase the number of TH+neurons and GFAP+cells in PD model mice(P<0.05,P<0.001),and reduce the expression of caspase-1,IL-1β,NLRP3 and p-IKK proteins in the brain of PD model mice(P<0.05).CONCLU-SION Gallic acid inhibits the activation of NF-κB signaling pathway and NLRP3 inflammasome by binding to β-arrestin2 to reduce astrocyte inflammation,and has a neuroprotective effect on MPTP-induced PD model mice.